The present invention relates to an extractor for bearings, bushings, sleeves, liners, and the like.
Many methods of extracting bearings, bushings, sleeves, liners and the like (hereinafter referred to generally as bushings) which are an interference fit in a housing often result in damage to the bushing and/or the housing.
Using a simple drift to drive out the bushing will score the housing and deform the end of the bushing. It also requires access to both ends of the housing.
Various pulling methods have been proposed.
U.S. Pat. Nos. 4,214,362 and 4,369,569 describe a tube puller in which an extractor cam forces gripping surfaces against the bushing inside wall, damaging the bushing and also risking distortion of the housing wall.
U.S. Pat. No. 5,249,342 describes an extractor which can be operated from one end of the housing. A cam is inserted through the bushing, followed by a collet. The collet has a number of legs and these are urged outwards by the cam to a predetermined diameter as the cam is withdrawn. Lips on the legs engage the distal end of the bushing so that the cam, collet and bushing are withdrawn together. Accurate sizing of the collet and cam ensure that there is no distortion of the bushing and no scoring of the housing surface, avoiding any need to repair or dress the housing and allowing re-use of the bushing when appropriate. However, the collets are expensive to manufacture, and the collet/cam assembly must be tailored to a particular bushing internal diameter.
GB-A-2370527, the contents of which are incorporated herein by reference, describes an extractor system in which an engaging device, for engaging the end of the bushing prior to extraction, comprises a plurality of separately formed engaging elements which are mechanically coupled together such as by clips or by a key on one element engaging a keyway on another element. This provides an elegant mechanism for producing engaging devices to match bushings of different diameter. However, the handling of small parts can be a drawback in some workshops.